Take-up mechanism for sewing-machines.



. J. LEATHEM.

TAKE-UP MECHANISM FOR SEWING MACHINES.

APPLICATION FILED SEPI- 3, I9I3- Patented Feb. 15, 1916.

2 SHEETSSHEET I.

III mm fjnntoz J. LEATHEM.

TAKE-UP MECHANISM FOR SEWING MACHINES. APPLICAIION FILED SPL3,1913.

1 1 7 1 ,858 v Patented Feb. 15, 1916.

2 SHEETS-SHEET 2.

QFFICE.

JAMES LEATHEM, 0F LEBANON, PENNSYLVANIA, ASSIGNOR TO HERMANN .AUKAM & 00., OF NEW 'YGBK, N. Y'., A'EORPORATION OF NEW YORK.

TAKE-U? MECHANISM FOR SEWING-MACHINES.

1,1'i1,ese.

Specification of Letters Patent.

latented Feb. 15, 1916.

Application filed September 1913. Serial No. 788,010.

citizen of theUnited' States, and a resident of Lebanon, in the county of Lebanon and State of Pennsylvania, have invented certain new and useful Improvements in Take- Up Mechanism for Sewing-Machines, of which the following is a specification.

My invention relates to improvements in take-up mechanisms for sewing machines, and comprises a take-up mechanism adaptable for very high speed operation, and capable of giving a very desirable motion to the take-up arm. I

My invention consists in the novel construction of the mechanism.

The object of my invention is to produc a take-up mechanism of simple construction and adapted for high speed operation, and which shall give a properly timed rapid upward motion to the take-up arm, together with a slow return movement of such arm, and gradual acceleration of the take up arm near both ends of its movement.

I will now proceed to describe my invention with reference to the accompanying drawings, and will then point out the novel features in claims. J

Figure 1 shows a front elevation of the head of a sewing machine provided with my improved take-up mechanism. Fig. 2 shows a transverse section of such head on the line wm of Fig. 1. Fig. 3 shows a detail longitudinal section of the crank arm and crank pin and associated parts of the machine in.- dicating the provision for lubricating such parts. Fig. 1 shows a detail elevation at a spacing sleeve mounted upon the crank pin. Fig. 5 shows a front elevation of a portion of the internal mechanism of the head of the machine, the front plate of such head and parts carried thereby having been removed, and Fig. 6 shows an elevation looking from the rear of the front plate of the head and parts carried thereby. Fig. 7 is a diagram showing the character of the move-v 3 designates the needle bar.

The particular needle mechanism shown is that ofmy Patent No. 1,017,567 dated February 13, 1912.

The needle bar, as is customary in such machines, is reciprocated up and down by means of a link 41 pivotally mounted upon a crank pin 5 of a counter-balanced crank arm 8 itself mounted upon the main shaft 7 of the machine, such link 4 being also pivotally mounted upon a stud 8 projecting from the needle bar 3. Rotation is communicated to a portion of the needle bar mechanism, for reasons explained in said Patent No. 1,017,567, by means of an arm 9 rotating with the crank pin 5 and provided with a beveled pinion 10 engaging a bevel gear 11 upon a sleeve 12, itself mounted upon the needle bar 3 and free to rotate with respect to. said needle bar, but restrained against axial movement as described in said Fatent No. 1,017,567. A

Upon the crank pin 5 is loosely mounted a lever arm 13 (Fig. 5) provided with a projecting guide-rod 14 rigid with respect to lever 13, and upon which is mounted a slidesleeve 15, itself provided with a hollow rock shaft 16 mounted in a bearing in the front plate 2 of the head; the construction being such that as the crank pin 5 rotates the guide-rod 14 moves up and down in the sleeve 15 imparting an oscillating motion to such sleeve, and to the rock shaft 16. It will be observed that with the parts arranged as shown and described, the guide surface of guide 14 is tangent to an imaginary circle having tor its center the axis of the crank pin. By this offsetting of the guide a materal improvement in the charactor of the motion of the take-up arm 17 hereinafter mentioned, is obtained, as compared with what would be obtained if such guide were radial to the crank pin. This rock shaft 16 projects beyond the front of the front plate 2 and has secured to it a take-up arm 17 provided at its end with an eye 17 for the reception of the needle thread. I have indicated in Fig. 1, in dotted lines, various positions of the take-up arm 17 showing its range of motion. I have also indicated in Fig. 1 the usual loop taker 18 mounted to rotate about a vertical axis.

This loop taker may be rotated by any of panion application filed September 3, 1913,

Serial No. 788,011. I prefer to rotate it at a speed which is a multiple of that of the rotation of the main shaft 7, and usually the mechanism of the machine is arranged to rotate such loop taker at twice the rotary speed of the main shaft 7.

Fig. 7 is a diagram showing the character of the motion given to the take-up arm by the mechanism above described. In this figure, various positions of the crank pin 5 are indicated by letters a, 7), 0-011. inclusive, and corresponding positions of the guide rod 14: are indicated byreference letters a, b, 0'm' inclusive, and. corresponding -posi tions of the end of the takeup arm. are indicated by reference letters a, b", cm inclusive. It will be seen that the take-up arm 17 starts to move to the right when the crank pin 5, and therefore the needle bar, have neared the upper limits of their movements, and that while the acceleration of the take-up arm toward the right is gradual, its movement, particularly between points is" and m is extremely rapid; after which the motion of the take-up arm is gradually retarded. In its return movement, the motion of the take-up arm is much slower, with gradual acceleration. and retardation. In other words, the motion of the take-up arm is slow while the hook or loop-taker 18 is taking the loop of the needle thread, while for drawing the stitchtight the motion of the take-up arm is extremely rapid through a Wide range. The remainder of the motion of the take-up arm is slow, as such motion is an idle motion. The acceleration of the take-up arm in both directions being gradual, and the parts of the take-up mechanism being light, and entirely free of lost motion, the take-up mechanism is capable of operating at high speed and is practically noiseless in operation.

As will be readily apparent to persons skilled in the design of machinery, by slight changes of proportions of parts in the design of thistake-up mechanism, the character of the motion given the take-up arm may be varied through a wide range, with-- out loss of the characteristic features of the mechanism, 5. 6., freedom from lost mo-- tion, gradual acceleration and retardation, rapid motion in one direction, and slow motion. in the other direction- For the lubrication of the parts of the take-up mechanism, the rock shaft. 16 is made hollow and usually contains absorbent material 19. It is provided with oil holes 20 communicating with oil ducts 21 in the top of the front plate 2. Thereby the lubrication of the bearing in the front plate 2 in which this rock shaft 16 works is pro vided for. The hollow bore of the rock shaft communicates with the hollow bore of the slide sleeve 15, and thus lubrication of the bore of the sleeve 15 and of the guide-rod 14.- is provided for. The crank pin5 is also hollow and contains absorbent material 19 and is provided with oil ports 22, as is also the spacing sleeve 23 on said rock shaft and the hub 24: of the arm 13. Thereby the lubrication of the bearing surfaces of members 5, 23 and 24 is provided for. The stud 8 is also hollow and contains absorbent material 25'and is provided with oil ports 26 for the lubrication of the bearing surfaces of said stud and the end of the link 4. For lightness, the guide rod 14: is made hollow.

What I claim is 1. A take-up mechanism for sewing machines comprising in combination a driving shaft having a crank arm. and crank pin, a lever arm mounted for oscillation on said crank pin and having as a rigid part of it a guide, rod extending from it tangentially to a circle of which thecenter is the axis of said crank pin, a take-up shaft mounted for oscillation and having a sleeve mounted to slide on the said. guide rod, and a take-up arm mounted on said take-up shaft.

2. A take-up mechanism. for sewing ma" chines comprising in combination a driving shaft having a crank arm and crank pin, an oscillatory guide member having an offset portion loosely mounted upon said crank pin, a take-up shaft mounted for oscillation having a sleeve slidably engaging said guide membensaid take-up shaft being provided with an oil passage for supplying oil to the engaging surfaces of said guide member and sleeve, and a take-up arm mounted on said. take-up shaft.-

3. A take-up mechanism for sewing machines comprising in combination a crank shaft having a crank arm and crank pin, a member mounted for oscillation on said crank pin and having projecting from it a guide rod, a hollow take-up shaft provided with a sleeve mounted upon said guide rod, the interior of said sleeve in communication with the interior of said take-up shaft, a bearing for said take-up shaft provided with an oil duct, said take-up shaft provided with an oil duct extending from its outer bearing surface to its interior, whereby oil from the outer bearing surface of such take-up shaft may reach the said guide sleeve and guide rod, and a take-up arm mounted on said take-up shaft.

4. A. take-up mechanism for sewing machines comprising a driving shaft having a crank arm, a hollow crank pin thereon, a take-up shaft mounted for oscillation, a bushing mounted upon said crank pin, a lever mounted upon said bushing and having as a rigid. part of it a guide member having sliding connection with said take-u In testimony whereof I have signed this shaft, said lever, bushing and hollow cran specification in the presence of two subscribpin having registering oil ducts whereby ing witnesses.

the interior of said crank pin forms an oil JAMES LEATHEM. 5 reservoir for the bearing surfaces of said Witnesses:

crank pin, bushings and lever, and a take- F. J. CRYSTAL,

up arm mounted upon said take-up shaft. D. A. DAVIES. 

